Sheet clamp having a one eared spreader bar



July 9, 1963 s. B. JONES SHEET CLAMP HAVING A ONE EARED SPREADER BAR Filed March 14, 1960 United States Patent O 3,096,679 SI-EET CLAMP HAVING A ONE EARED SPREADER BAR Sterling B. Jones, West Covina, Calif., assigner to Monogram Precision Industries, Inc., Culver City, Calif., a corporation of California Filed Mar. 14, 1960, Ser. No. 14,740 2 Claims. (Cl. S-)

This invention Irelates to securing devices, and more particularly to improvements in clamps for holding sheets of material together.

Sheet clamps are commonly employed for temporarily holding sheets of material together, e.g., metal panels that are to be riveted together. Typically, such .sheets are provided with a plurality of aligned openings to receive the rivets. To hold the sheets together as the riveting proceeds, clamps are used wherein elongated, slidable needles with enlarged heads extend from a clamp body through the aligned openings in the sheets. The sheets are clamped between the clamp body and the heads of the needles.

The clamping action is achieved by continually forcing the needles toward the clamp body. `In spring-action clamps, this is accomplished by means of a spring that surrounds and engages the needles within the clamp body, and a iixed spreader bar extending from the clamp body between fthe needles. The spring normally urges the needles therewith into the clamp body, so that the heads ride up on the spreader bar. Thus spread apart, the needles cannot pass into the clamp body, nor can they pass through the aligned openings in the sheets to be fastened.

To operate the clamp, the needles are forced against the spring until they override the spreader -bar and the enlarged heads come together. The heads are then passed through the aligned openings. The spreader bar also extends through such openings, so that upon releasing the force on the needles, the spring is free to urge the needles rearwardly, whereupon the heads ride up on the spreader bar to engage the adjacent sheet of material. To release the clamp, the needles are forced forwardly until the heads override the spreader bar and come together, whereupon the needles can be withdrawn through the openings. Upon release of the needles after they are withdrawn, the spring forces them rearwardly until their heads abut the clamp body.

In atypical spring clamp of the prior art, the spreader bar, which is a T-shaped element, becomes cocked in the assembly thereof with the spring and the needles. This is the type of clamp wherein the spring, the needles and the spreader bar are assembled together and placed in one end of the clamp body, and the body at its opposite end is closed to prevent the assembly from being dislodged therefrom. In such cocked position, the spreader bar will not readily pass through the openings, so it is forced. Such forcing causes damage to the sheets of material being fastened, and also to the clamp. The damage to the clamp in some instances is so severe that the clamp must be discarded. As will be apparent, :such prior art clamps are unduly costly to use.

Itis an object of this invention to provide a clamp structure that overcomes the above and other disadvantages of prior art clamps. A

It is another object of this invention to provide a spring clamp of the type described in which the spreader b'ar cannot be cocked in assembly.

It is also an object of this invention to provide an improved spring clamp having a minimum number of component parts of simple design and rugged construction.

The above and other objects and advantages of my invention will become apparent from the following descrip- 3,0%,679 Patented July 9, 1963 tion taken in conjunction with the accompanying drawing of an illustrative embodiment thereof, in which:

FIGURE l is an exploded view of the parts of the improved clamp of my invention;

FIGURE 2 is a longitudinal side view of the parts assembled in a clamp body, showing one end of the spring abutting the ear on one side of the spreader bar;

FIGURE 3 is a fragmentary plan view taken along the line 3-3 of FIGURE 2, showing more clearly the arrangement of the spring and the ear on the spreader bar .to prevent cooking of the spreader bar; and

FIGURE 4 is a fragmentary sectional view of the end portion of the clamp, showing the needles extended over the spreader bar to permit them to pass through the aligned openings in sheets to be fastened together.

Referring to FIGURES 1 3, there is shown a sheet clamp comprising a rod 10 ywhich terminates at one end in a pair of elongated needle elements 11, 12. The needles 11, 12 have enlarged lheads 13, 14, an-d are arranged so that the ends of the confronting faces of the heads 13, 14 are normally touching, and to this end the needles may be formed of spring metal.

The needles 11, 12 are surrounded by :a compression spring 15. As shown, the spring 15 at one end rests against a washer 16 that surrounds the fixed ends of the needles. In the particular arrangement illustrated, the diameter of the rod 10 is greater than the Vdistance between the remote surfaces of the needles, whereby to provide, at the iixed ends of said needles opposite the heads thereof, abutment means, `for retaining the spring in position, in the form of a radial shoulder or seat 17 for the washer 16.

The spring 15 at its opposite end abuts a washer 18 that surrounds the needles adjacent their heads 13, 14. As shown, there `are relatively sharp transitions between the heads and the main bodies of the needles, providing shoulders 19, 2t) adapted to engage the adjacent surface of the washer 18. The spring 15 normally is compressed sufficiently to cause the Washers 16, 18 to ibe seated against the shoulder 17 of the rod 10 and the shoulders 19, 20 of the heads 13, 14.

The heads 13, 14 4are normally separated by a spreader bar 21. The spreader bar 21 is a thin, generally rectangular element that extends at one end through the washer 18.

The spreader bar 21 is held in fixed spaced relation to the Washer 18 and the adjacent end of the spring 15. To this end, a short ear projection 22 is provided on one edge of the spreader bar 21, intermediate the ends of said bar and substantially at right angles to said one edge. The ear 22 is located ybetween the Washer 18 and that portion of the adjacent turn of the spring 15 that is spaced Ifrom the washer 18 a `distance equal to the length of the ear 22. Conversely, the ear 22 is made so that it iits between the washer 18 and the 4last turn of the spring 15 without binding. In this Way, the ear 22 and the spring 15 are in noninterfering relation, i.e., the spring 15 does not exert any thrust on the ear 2.2. The thrust is applied only against the washer 13 and the needles 1-1, 12, whereby the spreader bar is not skewed or cocked as in prior art clamp arrangements. In such arrangements, as where a T-sh-aped spreader bar is employed, the spring abuts the laterally extending portions, exerting a thrust thereon that cocks the spreader bar to one side. In the present arrangement, the Washer 18 and the last turn of the spring 15 essentially form the fixed end walls of a chamber or compartment for housing that portion of the spreader bar 21 carrying the ear 22. The iixed walls of this compartment serve to limit the spreader bar 21 against relative axial movement which may be caused Iby frictional drag of the needles 11, 12 over the surface of the spreader bar. However, in actual practice, this friotional drag is minimal, and there is essentially no tendency for the 3 spreader bar to mofve axially'in relation to said chamber or compartment.

To further aid in keepingthe spreader bar 21 properly centered, the width of thespreader bar is made substantially equal to the inner diameter of thespring 15.`

Since a substantial part of the spreader bar extends past itsear -22 into the spring, the spreader bar cannotbe cocked within the spring.

To assemble the parts as above described, the washer 16 is placedv around the needles and lowered to the fixed ends thereof. Then the springl is lowered over the needles and compressed. Next, the spreader bar 21 is locatedgbetween the needles and `againstthe end of the spring v1-5. In this position, the spreader bar is not between the heads 13, 14, thereby permitting them to Ibe in touching relation. With the heads thus close together, the washer 18 is slipped, over them. Then spreader bar 21 is movedtol separatethe heads of the needles, and the spring 15jis released, thereby to force the washer 1S against the shoulders 19,20.v The resultant sub-assembly will hold together and may be completed immediately or may be stored for subsequent completion.

With the subassembly thus prepared, the clamp assembly process is Icontinued by placing the Subassembly in a clampY body 25 (see FIGURE 2) with the heads; 13

14 extending from one end thereof. The body is peened over at its other end, whereby the washers cannot emerge from the body. The body has an external shoulder 26 to be engaged by `a forkedV jaw 27 of a pair of pliers. The end of the rod 141 that extendsfrom the body 25 is adapted to be engaged by theother jaw 28 of thepliers. Thus, forcing the jaws 27, 28 together causes the rod 10 and the needles 11, 12 t-o moverlongitudinally. When the heads 13, 14 have cleared the spreader 'bar 21 and come together, they are inserted through `aligned openings 29,

30 in sheets 31, 32 to be fastened (see FIGURE 4). Then.

the rod 10- is released to be retracted under the force` of the spring 15, whereupon the heads 13, 14 ride up onl the spreader bar 21, and the shoulders 19, 2t!- corne into engagement with the adjacentsheet 31. In this manner, as in priorart clamps, the sheets 31, 32 are firmly clamped between the heads 13, 14 and the clamp body 25.r

The arrangement of the spreader bar 21 in accordance with myinvention also helps to prevent rotation of the spreader bar relative to the spring 15. As shownin FIG- URES 2-4, the end of the springis 'disposed against the ear 22 and extends laterally therefrom. Thus, the ear 22 is effectively held against 4lateral movement between the end of the spring and the portion of the iinal turn adjacent the other side ofthe ear.

It will be apparent from the foregoing that while a particular form of my invention has been illustrated and described, various rmodiiications can be made without departing from the spirit and scope of my invention. Accordingly, I do not intend that my invention be limited, except las by the appended claims.

I claim:

1. A sheet clamp comprising: ahollow body having restricted openings at its ends, there-by providing transverse surfaces; a washer in said body having flat, substantially parallel sur-faces engaging the transverse surface at one end; a rod extending into the opposite end of said body `and having a ange engaging the transverse surface at said opposite end; a compressed coil spring extending between said flange :and said washer, a substantial portion of the end coil abutting the washer; a pair of needles xed at one end to said flange, said needles extending through said spring and said washer to the exterior of said body, the exterior ends of said needles having enlarged heads with surface portions to engage the outermost surface of said washer; -a spreader bar having a portion within said spring and extending through said washer and between said heads, said spreaderbar having parallel edges; and an ear extending substantially at right angles from one edge only -of said spreaderbar intermediate the ends of` said bar, said ear being located bef tween said washer and the adjacent end turn of vsaid spring, said ear being disposed adjacent the end of said endl turn, said portion ofthe bar within the spring having a width substantially equal to the inner diameter of the spring.

2. In a springfclamp having a clamprbody, an assembly to be positioned in the body comprising: `a pair of elongated needles extending through said clampy body, saidy needles having enlarged heads projecting from one end of said body, the transitions between remote sides ofl said needles and their heads .beingabrupt, the ends of the needles opposite the heads thereof being connected to the endv of a rod; an elongated plate having substantially parallel edges and lan ear on one edge only, said ear extending `at substantially fright angles to said `one ledge andl being intermediate the ends of said plate, said plate being disposed :between said enlarged headsgga compressed coil spring surrounding said needles and extending from said enlarged heads to said rod; said ear being disposed beside` References` Cited in the iileof this patent UNITED STATES PATENTS 2,280,403 Finlele Apr. 21, 1942 2,371,470 Rossmann- Mar. 13, 1945 2,388,603 De Mooy Nov. 6, 1945 2,397,892 Van Sittert Apr. 2, 1946 2,464,543- Modrey Mar. 15, 1949 2,561,098 Cole a- July 17, 1951 2,805,875 Modrey Sept. 10, 1957 

1. A SHEET CLAMP COMPRISING: A HOLLOW BODY HAVING RESTRICTED OPENINGS AT ITS ENDS, THEREBY PROVIDING TRANSVERSE SURFACES; A WASHER IN SAID BODY HAVING FLAT, SUBSTANTIALLY PARALLEL SURFACES ENGAGING THE TRANSVERSE SURFACE AT ONE END; A ROD EXTENDING INTO THE OPPOSITE END OF SAID BODY AND HAVING FLANGE ENGAGING THE TRANSVERSE SURFACE AT SAID OPPOSITE END; A COMPRESSED COIL SPRING EXTENDING BETWEEN SAID FLANGE AND SAID WASHER, A SUBSTANTIAL PORTION OF THE END COIL ABUTTING THE WASHER; A PAIR OF NEEDLES FIXED AT ONE TO SAID FLANGE, SAID NEEDLES EXTENDING THROUGH SAID SPRING AND SAID WASHER TO THE EXTERIOR OF SAID BODY, THE EXTERIOR ENDS OF SAID NEEDLES HAVING ENLARGED HEADS WITH SURFACE PORTIONS TO ENGAGE THE OUTERMOST SURFACE OF SAID WASHER; A SPREADER BAR HAVING A PORTION WITHIN SAID SPRING AND EXTENDING THROUGH SAID 